Question

There are 144 instructors who taught classes involving probability over the last year. 1/3 of these instructors are nice while the others are not. Of the 144 instructors, 83 of them asked questions about playing cards on their final exam. Of the nice instructors, 13 of them asked their students questions about playing cards on their final exam. If you randomly choose one of these instructors, what is the probability that they did not ask questions about playing cards on the final, given that they are nice?

Answer 1

the necessary calculation table :-

	nice instructor	not nice instructor	row total
asked questions about playing cards on their final	13	(83-13) = 70	83
did not ask questions about playing cards on their final	(48-13) = 35	(96-70) = 26	(144-83)= 61
column total	(144*1/3) = 48	(144-48) = 96	144

the probability that they did not ask questions about playing cards on the final, given that they are nice is :-

= P( they did not ask questions about playing cards on the final |  they are nice)

= number of nice instructors who did not ask questions about playing cards on the final / total number of nice instructors

*** if you have any doubts about the problem please mention it in the comment box... if satisfied please LIKE.